Method of requesting and reporting link quality in an EGPRS2 system

ABSTRACT

The link quality reporting method includes measuring link quality for received radio blocks, and if there is a modulation scheme with a largest number of radio blocks, reporting link quality for the modulation scheme, and if there is a plurality of schemes with the same number of radio blocks, reporting link quality for a modulation scheme selected using a predetermined method. Performance deterioration can be minimized in a link adaptation process.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority of U.S. Provisionalapplication Ser. No. 61/027,747 filed on Feb. 11, 2008, U.S. Provisionalapplication Ser. No. 61/050,626 filed on May 6, 2008, U.S. Provisionalapplication Ser. No. 61/052,982 filed on May 13, 2008, Korean PatentApplication No. 10-2008-0002625 filed on Jan. 9, 2008, Korean PatentApplication No. 10-2008-0012424 filed on Feb. 12, 2008, Korean PatentApplication No. 10-2008-0073911 filed on Jul. 29, 2008, and KoreanPatent Application No. 10-2008-0073910 filed on Jul. 29, 2008, which areincorporated by reference in their entirety herein.

BACKGROUND

1. Technical Field

The present invention relates to wireless communications, and moreparticularly, to a method of reporting link quality for radio blocksusing various modulation schemes in an enhanced general packet radioservice system (EGPRS) or an enhanced general packet radio service phase2 (EGPRS2) system and to a method of requesting uplink radio resourcesfrom a mobile station to a base station.

2. Related Art

Global system for mobile communication (GSM) is a radio technology whichhas been developed as a standardized system for radio communicationsystems in Europe and which has widely been deployed all over the world.General packet radio service (GPRS) was introduced to provide packetswitched data services in circuit switched data services provided by theGSM. The enhanced data rate for GSM evolution (EDGE) employs an 8-phaseshift keying (PSK) in addition to the Gaussian minimum shift keying(GMSK) employed in the GSM. The enhanced general packet radio service(EGPRS) represents the GPRS using the EDGE.

A packet data channel (PDCH) denotes a physical channel used forGPRS/EGPRS traffic. Examples of logical channels mapped onto the PDCHinclude a packet common control channel (PCCCH) used for control signalsrequired in packet transmission initialization, a packet data trafficchannel (PDTCH) for user data, a packet associated control channel(PACCH) for dedicated signalling, and so on.

An enhanced general packet radio service phase 2 (EGPRS2) supportingfurther various modulation and coding schemes has recently beingdeveloped. While the EGPRS supports only two modulation schemes (i.e.,GMSK and 8-PSK), the EGPRS2 supports five modulation schemes (i.e.,GMSK, quadrature phase shift keying (QPSK), 8-PSK, 16-quadratureamplitude modulation (QAM), and 32-QAM). There are two levels of EGPRS2,that is, EGPRS2-A and EGPRS2-B. The EGPRS2-A supports the GMSK, 8-PSK,16-QAM, and 32-QAM. The EGPRS2-B supports the GMSK, QPSK, 16-QAM, and32-QAM. A downlink EGPRS2-A uses modulation schemes MCS-1 to MCS-4 (MCSstands for Modulation and Coding Scheme) and DAS-5 to DAS-12 (DAS standsfor Downlink level A modulation and coding Scheme). An uplink EGPRS2-Auses modulation schemes MCS-1 to MCS-6 and UAS-7 to UAS-11 (UAS standsfor Uplink level A modulation and coding Scheme). A downlink EGPRS2-Buses modulation schemes MCS-1 to MCS-4 and DBS-5 to DBS-12 (DBS standsfor Downlink level B modulation and coding Scheme). An uplink EGPRS2-Buses modulation schemes MCS-1 to MCS-4 and UBS-5 to UBS-12 (UBS standsfor Uplink level B modulation and coding Scheme). A modulation andcoding scheme for each level in the EGPRS2 may be found in clause6.5.5.1.3 of 3GPP TS 43.064 V7.6.0 (2007-08) “Technical Specification;GSM/EDGE Radio Access Network; General Packet Radio Service (GPRS);Overall description of the GPRS radio interface; Stage 2 (Release 7)”.

An EGPRS/EGPRS2 system provides a multi-data rate by using variousmodulation and coding schemes. For example, data is transmitted withvarious data rates through the PDTCH. The data rate is regulated on thebasis of the link quality in a link adaptation process. If the linkquality is good, data is transmitted with a high data rate. On thecontrary, if the link quality is poor, data is transmitted with a lowdata rate. Data may be lost when transmitted according to a modulationand coding scheme that requires a data rate higher than achievable withthe link quality. In link adaptation, a data throughput is increasedusing the highest possible data rate by using a specific modulation andcoding scheme with a predetermined link quality.

For the link adaptation process, the link quality needs to be reportedfrom a mobile station (MS) to a base station (BS). In order for the MSto transmit packet data to a network, uplink radio resources have to beassigned. As described above, the EGPRS2 supports additional modulationschemes, and the MS supports the two EGPRS2 levels (i.e., EGPRS2-A andEGPRS2-B).

In the EGPRS/EGPRS2 system, the link quality between the base stationand the mobile station is represented with a bit error probability(BEP). The BEP is an expectation value of the actual bit error rate(BER) of a signal received by the mobile station through a radiochannel. The BEP is measured burst by burst. The base station selects asuitable modulation and coding scheme according to the reported linkquality.

The link adaptation can be performed in a most effective manner when thereported BEP most accurately estimates the actual BER. With the use ofadditional modulation schemes in the EGPRS2, there is a need for amethod of effectively reporting link quality according to the variousmodulation schemes.

SUMMARY

The present invention provides a method of reporting link quality forsome of a plurality of modulation schemes in an enhanced general packetradio service phase 2 (EGPRS2) system using the plurality of modulationschemes.

The present invention also provides a method of reporting link qualityto improve performance of a link adaptation process in an enhancedgeneral packet radio service phase 2 (EGPRS2) system using a pluralityof modulation schemes.

The present invention also provides a method of requesting uplink radioresources in an enhanced general packet radio service phase 2 (EGPRS2)system.

According to an aspect of the invention, the mobile terminal reportslink quality for radio blocks using a plurality of modulation schemes bydetermining a link quality parameter for each modulation scheme and eachtimeslot assigned to the mobile terminal, determining the number oftimes each modulation scheme is used in each of the assigned timeslotsover a reporting period, selecting a modulation scheme per timeslot andreporting to a network, for each assigned timeslot, the selectedmodulation scheme and the corresponding link quality parameter.

The invention also relates to a corresponding mobile terminal comprisinga radio frequency (RF) unit adapted to receive radio blocks using aplurality of modulation schemes and a processor coupled with the RF unitand adapted for determining a link quality parameter for each modulationscheme and each timeslot assigned to the mobile terminal, determiningthe number of times each modulation scheme is used in each of theassigned timeslots over a reporting period, selecting a modulationscheme per timeslot and reporting to a network, for each assignedtimeslot, the selected modulation scheme and the corresponding linkquality parameter.

Advantageously, the selected modulation scheme is the most usedmodulation scheme per timeslot over the reporting period.

In a specific embodiment the selected modulation scheme is themodulation scheme with which the mobile terminal has received thelargest number of radio blocks per timeslot over the reporting period.

In one embodiment, determining the link quality parameter comprisesmeasuring a bit error probability (BEP) per burst, averaging themeasured BEP per radio block and computing the link quality parameterbased on the measured and averaged BEP per modulation scheme and pertime slot.

In one case the plurality of modulation schemes comprises Gaussianminimum shift keying (GMSK), quadrature phase shift keying (QPSK),8-phase shift keying (PSK), 16-quadrature amplitude modulation (QAM),and 32-QAM.

Alternatively, the plurality of modulation schemes comprises GMSK, QPSK,8-PSK, 16-QAM normal symbol rate (NSR), 16-QAM higher symbol rate (HSR),32-QAM NSR, and 32-QAM HSR.

The invention also relates to a method of reporting link quality forradio blocks using a plurality of modulation schemes, the methodcomprising, performed in a mobile terminal, determining a link qualityparameter for each modulation scheme and each timeslot assigned to themobile terminal, determining the number of times each modulation schemeis used in each of the assigned timeslots over a reporting period,selecting at least one modulation scheme and reporting link qualityinformation for said selected modulation scheme to a network. In thismethod selecting comprises selecting the most used modulation scheme andif there are several mostly used modulation schemes, selecting onemodulation scheme among said mostly used modulations schemes based onits modulation order or its error rate.

Similarly, the invention relates to a mobile terminal comprising a radiofrequency (RF) unit adapted to receive radio blocks using a plurality ofmodulation schemes and a processor coupled with the RF unit and adaptedfor determining a link quality parameter for each modulation scheme andeach timeslot assigned to the mobile terminal determining the number oftimes each modulation scheme is used in each of the assigned timeslotsover a reporting period, selecting at least one modulation scheme andreporting link quality information for said selected modulation schemeto a network. In this mobile terminal selecting comprises selecting themost used modulation scheme and if there are several mostly usedmodulation schemes, selecting one modulation scheme among said mostlyused modulations schemes based on its modulation order or its errorrate.

Advantageously, the invention further comprises selecting anothermodulation scheme, wherein said other modulation is the most usedmodulation scheme among not selected modulation schemes and if there areseveral not selected mostly used modulation schemes, selecting onemodulation scheme among said not selected mostly used modulation schemesbased on its modulation order or its error rate.

In one embodiment, selecting one modulation scheme among said mostlyused modulations schemes or said not selected mostly used modulationschemes comprises selecting a high-order modulation scheme.

Alternatively, selecting one modulation scheme among said mostly usedmodulations schemes or said not selected mostly used modulation schemescomprises selecting a low-order modulation scheme.

In another alternative selecting one modulation scheme among said mostlyused modulations schemes or said not selected mostly used modulationschemes comprises selecting a modulation scheme with a low mean biterror probability (BEP).

In another alternative wherein selecting one modulation scheme amongsaid mostly used modulations schemes or said not selected mostly usedmodulation schemes comprises selecting a modulation scheme with a highmean BEP.

In one embodiment, said link quality information comprises the linkquality parameter for each selected modulation scheme for each timeslot.

Alternatively, said link quality information comprises an averaged valueof the link quality parameters of each selected modulation scheme overseveral assigned timeslots.

In one embodiment, determining the link quality parameter comprisesmeasuring a bit error probability (BEP) per burst, averaging themeasured BEP per radio block and computing the link quality parameterbased on the measured and averaged BEP per modulation scheme and pertime slot.

Furthermore, the invention also relates to a method of reporting linkquality for radio blocks using a plurality of modulation schemes, themethod comprising, performed in a mobile terminal: determining a linkquality parameter for each modulation scheme and each timeslot assignedto the mobile terminal, determining the number of times each modulationscheme is used in the assigned timeslots over a reporting period,selecting at least one modulation scheme and reporting to a network theselected modulation scheme and corresponding link quality information.In this method, selecting comprises: determining a subset of modulationschemes among a set of available modulation schemes and selectingmodulation schemes among the sole modulation schemes of said subset.

The invention also relates to a corresponding mobile terminal comprisinga radio frequency (RF) unit adapted to receive radio blocks using aplurality of modulation schemes and a processor coupled with the RF unitand adapted for: determining a link quality parameter for eachmodulation scheme and each timeslot assigned to the mobile terminal,determining the number of times each modulation scheme is used in theassigned timeslots over a reporting period, selecting at least onemodulation scheme and reporting to a network the selected modulationscheme and corresponding link quality information. In this mobileterminal, selecting comprises: determining a subset of modulationschemes among a set of available modulation schemes and selectingmodulation schemes among the sole modulation schemes of said subset.

In one embodiment, the set of available modulation schemes comprisesseven modulations schemes and the subset comprises four modulationschemes.

Advantageously, the plurality of available modulation schemes compriseGMSK, QPSK, 8-PSK, 16-QAM normal symbol rate (NSR), 16-QAM higher symbolrate (HSR), 32-QAM NSR, and 32-QAM HSR.

In one embodiment, selecting a modulation scheme comprises selecting themodulation scheme which is the most used in one timeslot and among themodulation schemes of the subset.

Advantageously, said link quality information comprises the link qualityparameter for each selected modulation scheme for each timeslot.

Alternatively, said link quality information comprises an averaged valueof the link quality parameters of each selected modulation scheme overseveral assigned timeslots.

In one embodiment, determining the link quality parameter comprises:measuring a bit error probability (BEP) per burst, averaging themeasured BEP per radio block and computing the link quality parameterbased on the measured and averaged BEP per modulation scheme and pertime slot.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a wireless communication system.

FIG. 2 is a block diagram illustrating constitutional elements of amobile station.

FIG. 3 shows a concept of a radio block.

FIGS. 4 and 5 are flow diagrams illustrating a method of reporting linkquality according to two embodiments of the present invention.

FIGS. 6 and 7 are flow diagrams illustrating a method of requestinguplink radio resources according to two embodiments of the presentinvention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 is a block diagram illustrating a wireless communication system.This example shows a network based on an enhanced general packet radioservice phase 2 (EGPRS2). Wireless communication systems are widely usedto provide a variety of communication services of voice, packet data,and so on.

Referring to FIG. 1, a mobile station (MS) 10 is a communicationinstrument carried by a user and may be called using other terms such asuser equipment (UE), a user terminal (UT), and a subscriber station(SS), a wireless device, etc.

The communication system also comprises a base station (BS) 20 whichincludes a base transceiver station (BTS) 22 and a base stationcontroller (BSC) 24. The BTS 22 communicates with the MS 10 in acellular area through a radio interface and performs a synchronizationfunction with the MS 10. The BSC 24 interfaces at least one BTS 22 witha mobile switching center (MSC) 30. The BS 20 may be called a basestation subsystem, a Node-B, or an access point.

The MSC 30 connects the BS 20 to a different kind of network such as apublic switching telephone network (PSTN) 65 or a public land mobilenetwork (PLMN) through a gateway MSC (GMSC) 60. A visitor locationregister (VLR) 40 stores temporary user data, which includes informationon the roaming of all the MSs 10 in the service area of the MSC 30. Ahome location register (HLR) 50 includes information on all thesubscribers in the home network. A serving GPRS support node (SGSN) 70takes in charge the management of the mobility of the subscribers. Agateway GPRS data network (GGSN) 80 routes a packet at the currentposition of the MS 10 to interface the MS with an external packet datanetwork such as a public data network (PDN) 85.

A temporary block flow (TBF) is a logical connection offered by twomedium access control (MAC) entities so as to support the unidirectionaltransfer of a radio link control (RLC) protocol data unit (PDU) on basicphysical subchannels. The TBF is not provided in a packet idle mode. Atleast one TBF is provided in a packet transfer mode. In the packettransfer mode, radio resources on one or more packet data physicalchannels for the transfer of packet data are assigned to the MS.MAC-idle state means a MAC-control-entity state where no basic physicalsubchannel is assigned. A temporary flow identity (TFI) is assigned toeach TBF by the network. The MS assumes that the TFI value is uniqueamong concurrent TBFs in the same direction (uplink or downlink) on allpacket data channels (PDCHs) used for the TBFs. The same TFI value maybe used concurrently for TBFs on other PDCHs in the same direction andfor TBFs in the opposite direction.

A TBF for the GPRS is referred to as a GPRS TBF. A TBF for the EGPRS isreferred to as an EGPRS TBF. A TBF for the EGPRS2 is referred to as anEGPRS2 TBF. A TBF for the EGPRS2-A is referred to as an EGPRS2-A TBF. ATBF for the EGPRS2-B is referred to as an EGPRS2-B TBF.

FIG. 2 is a block diagram illustrating constitutional elements of an MS.An MS 50 includes a processor 51, a memory 52, a radio frequency (RF)unit 53, a display unit 54, and a user interface unit 55. The memory 52is coupled to the processor 51 and stores an MS operating system,applications, and general files. The display unit 54 displays a varietyof information of the MS 50 and may use well-known elements such asliquid crystal display (LCD), organic light emitting diode (OLED)display, etc. The user interface unit 55 can be configured with acombination of well-known user interfaces such as keypad, touch screen,etc. The RF unit 53 is coupled to the processor 51 and transmits and/orreceives radio signals.

The processor 51 measures and reports link quality for radio blocksreceived through the RF unit 53. Further, the processor 51 requests thenetwork to assign radio resources for uplink transmission.

FIG. 3 shows a concept of a radio block.

Referring to FIG. 3, one time division multiple access (TDMA) frameincludes 8 timeslots TS0, TS1, . . . , and TS7 in an EGPRS/EGPRS2system. The radio block consists of 4 timeslots, each of which belongsto a different TDMA frame. For example, the radio block may beconfigured by selecting the 1^(st) timeslot TS0 of each of fourconsecutive frames. Although the 1^(st) timeslot TS0 is selected herein,it is also possible to select other timeslots. This structure of theradio block is exemplary purpose only. The radio block may be composedof 4 timeslots over 2 TDMA frames.

A channel, i.e. a timeslot sequence, uses the same timeslot number inevery TDMA frame and is defined by a timeslot number and a TDMA framenumber sequence. A timeslot sequence is regarded as a timeslot unlessthere is any explicit different explanation in this description.

A mean bit error probability (BEP) (i.e., MEAN_BEP) for one radio blockcan be obtained according to Equation 1 below.

$\begin{matrix}{{MEAN\_ BEP}_{block} = {\frac{1}{4}{\sum\limits_{i = 1}^{4}{BEP}_{{burst}\mspace{14mu} i}}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In Equation 1, BEP_(burst i) denotes a BEP for an i^(th) burst. A burstdenotes information carried on one timeslot. Here, one timeslot means asingle timeslot in one TDMA frame.

A coefficient of variation of BEP (i.e., CV_BEP) for the radio block canbe obtained according to Equation 2 below.

$\begin{matrix}{{CV\_ BEP}_{block} = \frac{\sqrt{\frac{1}{3}{\sum\limits_{k = 1}^{4}\left( {{BEP}_{{burst}\mspace{11mu} k} - {\frac{1}{4}{\sum\limits_{i = 1}^{4}{BEP}_{{burst}\mspace{14mu} i}}}} \right)^{2}}}}{\frac{1}{4}{\sum\limits_{i = 1}^{4}{BEP}_{{burst}\mspace{14mu} i}}}} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

The link quality parameter is obtained by averaging BEPs for all radioblocks dedicated to an MS with respect to each channel (timeslot) andeach modulation scheme. A reliability R_(n) of quality parameters foreach modulation scheme is defined as expressed by Equation 3 below.

R _(n)=(1−e)·R _(n-1) +e·x _(n) ,R ⁻¹=0  [Equation 3]

In Equation 3, n denotes an iteration index which is increased for eachdownlink radio block. The parameter e denotes a forgetting factor forperforming filtering on the MSs. The forgetting factor e can bedetermined according to a BEP period transmitted from the BS. Theforgetting factor e can be delivered to the MS by using a systeminformation message broadcast from the BS. In some cases an optionalparameter is transmitted in dedicated messages. Depending on which BEPperiod parameter is used, the filtering can be the same for all MS orcan be specific. The parameter x_(n) is a value indicating apresence/absence of a link quality parameter for an n^(th) radio blockwith respect to each modulation scheme. The value x_(n) may be ‘0’ or‘1’ according to the presence/absence of the link quality parameter.

By using the reliability, with respect to radio blocks having a TFI ofthe MS itself, the MS obtains the MEAN_BEP and CV_BEP for each timeslotaccording to the following equations.

$\begin{matrix}{{{MEAN\_ BEP}{\_ TN}_{n}} = {{{\left( {1 - {e\; \frac{x_{n}}{R_{n}}}} \right) \cdot {MEAN\_ BEP}}{\_ TN}_{n - 1}} + {e\; {\frac{x_{n}}{R_{n}} \cdot {MEAN\_ BEP}_{{block},n}}}}} & \left\lbrack {{Equation}\mspace{14mu} 4} \right\rbrack \\{{{CV\_ BEP}{\_ TN}_{n}} = {{{\left( {1 - {e\; \frac{x_{n}}{R_{n}}}} \right) \cdot {CV\_ BEP}}{\_ TN}_{n - 1}} + {e\; \frac{x_{n}}{R_{n}}{CV\_ BEP}_{{block},n}}}} & \left\lbrack {{Equation}\mspace{14mu} 5} \right\rbrack\end{matrix}$

Herein, the obtained link quality parameters are for radio blocks formedusing one timeslot per frame. Here, one timeslot means a single timeslotin one TDMA frame.

In the EGPRS/EGPRS2 system, a plurality of timeslots can be assigned tothe MS. Thus, for each modulation scheme, the MEAN_BEP and CV_BEP areobtained by performing an averaging operation over all channels assignedto the MS (i.e., timeslots for the received radio blocks having the sameTFI as the MS). This averaging is performed over a reporting period.

$\begin{matrix}{{MEAN\_ BEP}_{n} = \frac{\sum\limits_{j}{{R_{n}^{(j)} \cdot {MEAN\_ BEP}}{\_ TN}_{n}^{(j)}}}{\sum\limits_{j}R_{n}^{(j)}}} & \left\lbrack {{Equation}\mspace{14mu} 6} \right\rbrack \\{{CV\_ BEP}_{n} = \frac{\sum\limits_{j}{{R_{n}^{(j)} \cdot {CV\_ BEP}}{\_ TN}_{n}^{(j)}}}{\sum\limits_{j}R_{n}^{(j)}}} & \left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack\end{matrix}$

Herein, n denotes an iteration index at the time of reporting, and jdenotes a channel number. When a new cell is selected or when an MS isentering a packet transfer mode or a MAC-shared mode, the iterationindex n is reset to ‘0’. If a new timeslot is assigned for a downlinkTBF, then MEAN_BEP_TNn-1, CV_BEP_TNn-1, and Rn-1 for that timeslot arereset to ‘0’.

The MS reports all MEAN_BEPs and CV_BEPs which are calculated accordingto Equations 6 and 7 above with respect to each modulation scheme.Further, according to the request of the network, the MS can reportmeasurement values for each timeslot, that is, MEAN_BEP_TN andCV_BEP_TN.

As described above, in the EGPRS/EGPRS2, the link quality is measured,calculated and reported for each modulation scheme. Therefore, if thelink quality can be reported for all modulation schemes used in theEGPRS2, an optimal link adaptation can be performed. However, reportingof the link quality for all modulation schemes results in a signallingoverhead and thus may deteriorate the data rate. Moreover, the overheadis too large to report the link quality for all modulation schemes forevery assigned timeslot.

According to a current EGPRS/EGPRS2 standard, a packet downlinkassignment message is used as a control message related to the linkquality report. Table 1 below shows a part of the content of the packetdownlink assignment message disclosed in clause 11.2.7 of 3GPP TS 44.060V7.10.0 (2007-09) “Technical Specification Group GSM/EDGE Radio AccessNetwork; General Packet Radio Service (GPRS); Mobile Station (MS)-BaseStation System (BSS) interface; Radio Link Control/Medium Access Control(RLC/MAC) protocol (Release 7)”.

TABLE 1 < Packet Downlink Assignment message content > ::=  ...   { 0 |1 < EGPRS Window Size : < EGPRS Window Size IE >>     <LINK_QUALITY_MEASUREMENT_MODE : bit (2) >     <EGPRS2_LINK_QUALITY_MEASUREMENT_MODE :     bit (1) >     { 0 | 1 <BEP_PERIOD2 : bit(4) > } }  ...

In Table 1, the ‘LINK_QUALITY_MEASUREMENT_MODE’ field determines ameasurement value included in ‘EGPRS Timeslot Link Quality MeasurementsType 2’. The ‘EGPRS2_LINK_QUALITY_MEASUREMENT_MODE ’ field determines ameasurement value included in ‘EGPRS BEP Link Quality Measurements Type2’. The ‘EGPRS Timeslot Link Quality Measurements Type 2’ and the ‘EGPRSBEP Link Quality Measurements Type 2’ are information elements (IEs)included in an EGPRS packet downlinkacknowledgement/negative-acknowledgement (Ack/Nack) message. The EGPRSpacket downlink Ack/Nack message indicates a state of a received RLCdata block and is an uplink message transmitted through a packetassociated control channel (PACCH) to report downlink channel quality.

The ‘EGPRS BEP Link Quality Measurements Type 2’ includes informationspecified using the ‘EGPRS2 LINK QUALITY MEASUREMENT MODE’ field. If avalue of the ‘EGPRS2 LINK QUALITY MEASUREMENT MODE’ field is ‘0’, the MSreports MEAN_BEP and CV_BEP for all modulation schemes used in thereceived radio blocks by using the ‘EGPRS BEP Link Quality MeasurementsType 2’. If the value of the ‘EGPRS2_LINK_QUALITY_MEASUREMENT_MODE’field is ‘1’, the MS reports MEAN_BEP and CV_BEP for two modulationschemes by using the ‘EGPRS BEP Link Quality Measurements Type 2’. Table2 below shows a part of the content of the ‘EGPRS BEP Link QualityMeasurements Type 2’ disclosed in clause 12.5a.3 of 3GPP TS 44.060V7.10.0 (2007-09).

TABLE 2 <EGPRS BEP Link Quality Measurements Type 2 IE> ::=   { 0 | 1 <GMSK_MEAN_BEP : bit (5) > < GMSK_CV_BEP : bit (3) >}   { 0 | 1 <8PSK_MEAN_BEP : bit (5) > < 8PSK_CV_BEP : bit (3) > }   { 0 | 1 <QPSK_MEAN_BEP : bit (5) > < QPSK_CV_BEP : bit (3) > }   { 0 | 1 <16QAM_MEAN_BEP : bit (5) > < 16QAM_CV_BEP : bit (3) > }   { 0 | 1 <32QAM_MEAN_BEP : bit (5) > < 32QAM_CV_BEP : bit (3) > };

The ‘EGPRS Timeslot Link Quality Measurements Type 2’ includesinformation specified using the ‘LINK_QUALITY_MEASUREMENT_MODE’ field.Table 3 below shows a part of the content of the ‘EGPRS Timeslot LinkQuality Measurements Type 2’ disclosed in clause 12.5a.3 of 3GPP TS44.060 V7.10.0 (2007-09).

TABLE 3 <EGPRS Timeslot Link Quality Measurements Type 2 IE> ::= < BEPMeasurement Report Struct > ::=   < Reported_Modulations: bit (3) >   {0 | 1 { 0 <MODULATION_1_MEAN_BEP_TN0 : bit (4) > | 1 <MODULATION_2_MEAN_BEP_TN0 : bit (4) >} }   { 0 | 1 { 0<MODULATION_1_MEAN_BEP_TN1 : bit (4) > | 1 < MODULATION_2_MEAN_BEP_TN1 :bit (4) >} }   { 0 | 1 { 0 <MODULATION_1_MEAN_BEP_TN2 : bit (4) > | 1 <MODULATION_2_MEAN_BEP_TN2 : bit (4) >} }   { 0 | 1 { 0<MODULATION_1_MEAN_BEP_TN3 : bit (4) > | 1 < MODULATION_2_MEAN_BEP_TN3 :bit (4) >} }   { 0 | 1 { 0 <MODULATION_1_MEAN_BEP_TN4 : bit (4) > | 1 <MODULATION_2_MEAN_BEP_TN4 : bit (4) >} }   { 0 | 1 { 0<MODULATION_1_MEAN_BEP_TN5 : bit (4) > | 1 < MODULATION_2_MEAN_BEP_TN5 :bit (4) >} }   { 0 | 1 { 0 <MODULATION_1_MEAN_BEP_TN6 : bit (4) > | 1 <MODULATION_2_MEAN_BEP_TN6 : bit (4) >} }   { 0 | 1 { 0<MODULATION_1_MEAN_BEP_TN7 : bit (4) > | 1 < MODULATION_2_MEAN_BEP_TN7 :bit (4) >} };

The ‘Reported_Modulations’ field indicates for each timeslot tworeported modulation schemes. The MS reports MEAN_BEP for the most usedmodulation scheme during a reporting period between the two modulationschemes specified using the ‘Reported_Modulations’ field. Table 4 belowshows the content of the ‘Reported_Modulations’ field disclosed inclause 12.5a.3 of the reference.

TABLE 4 Reported_Modulations (3 bit field) bit 3 2 1 MODULATION_1MODULATION_2 For EGPRS2-A: 0 0 0 GMSK 8PSK 0 0 1 GMSK 16QAM 0 1 0 GMSK32QAM 0 1 1 8PSK 16QAM 1 0 0 8PSK 32QAM 1 0 1 16QAM 32QAM 1 1 0 reserved1 1 1 reserved For EGPRS2-B: 0 0 0 GMSK QPSK 0 0 1 GMSK 16QAM 0 1 0 GMSK32QAM 0 1 1 QPSK 16QAM 1 0 0 QPSK 32QAM 1 0 1 16QAM 32QAM 1 1 0 reserved1 1 1 reserved

When the link quality is reported using the ‘EGPRS Timeslot Link QualityMeasurements Type 2’ according to the aforementioned method, there areseveral problems as indicated below.

First, reporting of link quality for a modulation scheme to be reportedmay be unsuccessful. For example, it is assumed that an MS supportingthe EGPRS2-A uses ‘000’ as a value for the ‘Reported_Modulations’ field.That is, for each assigned timeslot, the MS selects the GMSK and 8-PSK,and reports link quality for the most used modulation scheme between theGMSK and the 8-PSK. It is also assumed that timeslots 1, 2, 3, and 5 areassigned to the MS. According to the conventional method, if the mostused modulation scheme for the timeslots 1, 2, and 5 is the GMSK or8-PSK and the most used modulation scheme for the timeslot 3 is the16-QAM, then the MS cannot report link quality for the 16-QAM at thetimeslot 3 and thus have to report link quality for the GMSK or 8-PSK.This is because the ‘Reported_Modulations’ field indicates only twospecified modulation schemes. Therefore, if a specific modulation schemeis more used in one of the assigned timeslots than the modulationschemes indicated using the ‘Reported_Modulations’ field, the MS cannotreport link quality for the specific modulation scheme in that timeslot.

Second, link quality may be reported in a duplication manner. Accordingto the value of the ‘EGPRS2 LINK QUALITY MEASUREMENT MODE’ field, the MSreports link quality for all modulation schemes or for two modulationschemes by using the ‘EGPRS BEP Link Quality Measurements Type 2’. The‘EGPRS BEP Link Quality Measurements Type 2’ is regularly reported tothe network. The ‘EGPRS Timeslot Link Quality Measurements Type 2’ isirregularly reported according to the value of the ‘LINK QUALITYMEASUREMENT MODE’ field. That is, the network is regularly provided withan average link quality for all assigned timeslots with respect to allmodulation schemes or to two modulation schemes by using the ‘EGPRS BEPLink Quality Measurements Type 2’. When considering unpredictable andvariable wireless environment, it is better for the network to receivemany pieces of information regarding link quality. However, according tothe conventional method of reporting link quality, when the value of the‘EGPRS2 LINK QUALITY MEASUREMENT MODE’ field is ‘1’, the networkreceives-almost duplicated information via the ‘EGPRS BEP Link QualityMeasurements Type 2’ and the ‘EGPRS Timeslot Link Quality MeasurementsType 2’, unless the MS experiences fast fading. A difference of the twoIEs lies in that one IE includes ‘per timeslot MEAN_BEP’ and the otherIE includes ‘non-per timeslot MEAN_BEP’. Thus, the link quality reportedusing the two IEs can be regarded as duplicated information.

Third, link quality may be reported for an unused timeslot. Assume thattimeslots are reconfigured during the reporting period, and that sometimeslots assigned through timeslot reconfiguration are not the same astimeslots used before timeslot reconfiguration. According to theconventional method, the MS can consider the use of one or severaltimeslots which are no longer used after the timeslot reconfigurationwhen two modulation schemes are selected. As a result, the MS may not beable to correctly report link quality after timeslot reconfiguration. Itis undesirable to consider the use of the timeslot which is no longerused. The MS needs to report link quality for currently assignedtimeslots.

Fourth, a link state may not be able to be correctly used. From theperspective of a statistical analysis, when a sufficiently large numberof samples are used, a representative value is an average value of thesamples. In a wireless environment, there are numerous factors (i.e.,deep fading, scatter, interference, etc,) that distort an originalsignal. In an arbitrarily variable wireless environment, link qualitycan be useful in the statistical analysis when a small number of radioblocks is guaranteed for a reported modulation scheme. According to theconventional method, modulation schemes indicated using the‘Reported_Modulations’ field may not be related to the number of radioblocks in each assigned timeslot. This means that the number of radioblocks for the modulation schemes indicated using the ‘ReportedModulations’ field for each assigned timeslot cannot guarantee thesmallest number of radio blocks required for the effective statisticalanalysis. Considering an unnecessary sample that experiences devastatingfast fading due to an instantaneous large obstacle, the influence of theunnecessary sample cannot be eliminated when an insufficient numbersamples are averaged. Therefore, a current link state may not beappropriately indicated using the reported link quality.

FIG. 4 is a flow diagram illustrating a method of reporting link qualityaccording to an embodiment of the present invention.

Referring to FIG. 4, in a step S210, a network configures a link qualityreport and provides instructions to an MS through a packet downlinkassignment message. To assign a downlink resource to the MS, the packetdownlink assignment message is transmitted on a packet common controlchannel (PCCCH) or a packet associated control channel (PACCH).

Table 5 below shows an example of an information element (IE) includedin the packet downlink assignment message to configure the link qualityreport.

TABLE 5 < Packet Downlink Assignment message content > ::=  ...   { 0 |1 < EGPRS Window Size : < EGPRS Window Size IE >>     <LINK_QUALITY_MEASUREMENT_MODE : bit (2) >     <EGPRS2_LINK_QUALITY_MEASUREMENT_MODE :     bit (1) >     { 0 | 1 <BEP_PERIOD2 : bit(4) > } }  ...

Each field of Table 5 above is described in Table 6 below.

TABLE 6 EGPRS Window Size This information element defines the windowsize to be used in an EGPRS TBF. The network sets the window sizeaccording to the number of timeslots assigned in the direction of theTBF. LINK_QUALITY_MEASUREMENT_MODE (2 bit field) This field determinesthe measurements to be included within the EGPRS Timeslot Link QualityMeasurements IE or EGPRS Timeslot Link Quality Measurements Type 2 IE.bit 2 1 0 0 The MS does not report either interference measurements (γvalues) or per slot BEP measurements. 0 1 The MS reports availableinterference measurements (γ values) for timeslots 0 through 7. The γvalue is defined in 3GPP TS 45.008. No per slot mean BEP measurementsshall be reported. 1 0 The MS reports the mean BEP on each assigned timeslot. In case of EGPRS, the MS reports the mean BEP measurementcorresponding to the modulation for which it has received a largernumber of blocks since the previous report. In case of EGPRS2, the MSreports both MEAN_BEP_TNx and REPORTED_MODULATION (see below). The MSmakes BEP measurements only on Radio Blocks intended for it. Nointerference measurements (γ values) shall be reported. 1 1 The MSreports the mean BEP on each assigned time slot. In case of EGPRS, theMS reports the mean BEP measurement corresponding to the modulation forwhich it has received a larger number of blocks since the previousreport. In case of EGPRS2, the MS reports both MEAN_BEP_TNx andREPORTED_MODULATION (see below). The MS makes BEP measurements only onRadio Blocks intended for it. In addition to mean BEP, the MS reportsinterference measurements (γ values) for no more than four time slots.If the MS has interference measurements for more than four timeslots toreport, the selection of timeslots for which measurements are includedin each message is implementation specific, subject to the requirementthat a measurement for each time slot, unless not available (see 3GPP TS45.008), is included in at least every other report.EGPRS2_LINK_QUALITY_MEASUREMENT_MODE (1 bit field) This field determinesthe measurements to be included within the EGPRS BEP Link QualityMeasurements Type 2 IE. It is applicable only to MSs with one or moredownlink TBFs using EGPRS2. bit 0 The MS reports in the EGPRS BEP LinkQuality Measurements Type 2 IE the mean_BEP and CV_BEP for allmodulation schemes used on blocks which it has received since theprevious report 1 The MS reports in the EGPRS BEP Link QualityMeasurements Type 2 IE the mean_BEP and CV_BEP for the two modulationschemes with the highest number of blocks received since the previousreport, unless only one modulation scheme was used on all blocksreceived since the previous report, in which case the mean_BEP andCV_BEP for this modulation scheme only shall be reported. BEP_PERIOD2 (4bit field) This field contains a constant which is used for filteringchannel quality measurements in EGPRS. For details see 3GPP TS 45.008.Range: 0 to 15

The ‘LINK_QUALITY_MEASUREMENT_MODE’ field is used to configure a linkquality report (i.e., MEAN_BEP_TN and/or CV_BEP_TN) for each timeslot.The ‘EGPRS2_LINK_QUALITY_MEASUREMENT_MODE’ field is used to configure anaverage link quality report (i.e., MEAN_BEP and/or CV_BEP) throughoutall assigned timeslots. In particular, if a value of the‘LINK_QUALITY_MEASUREMENT_MODE’ field is ‘10’ or ‘11’, the MS selectsthe modulation scheme which is the most used in a specific timeslotwithin all the assigned timeslots since the last report, and reports theselected modulation scheme (i.e., REPORTED_MODULATION) and link quality(i.e., MEAN_BEP_TNx) for the selected modulation scheme. In other words,the mobile station shall report the modulation scheme which has receivedthe largest number of radio blocks on each currently assigned timeslotas well as the channel quality parameter for that modulation scheme.

In a Step 220, the network transmits a radio block to the MS. Thetransmission is made in a packet transfer mode.

In a step 230, the MS determines whether the radio block has theidentifier of the MS itself, that is, the TFI of the MS itself. Whiledownlink TBF transmission is made, the MS measures received (Rx) signalquality. The signal quality is measured for the radio block of aspecified MS. According to the TFI, the MS determines whether thereceived radio block is dedicated for the MS itself. For example, whenan RLC/MAC data block is transmitted using the radio block, the MS canconfirm the TFI through an RLC/MAC header since the RLC/MAC headeralways includes the TFI.

In a step 240, the MS measures the link quality upon confirming the TFI.The MS measures the link quality for the radio blocks including a TFIidentical to the TFI assigned to the MS itself. The signal quality ofeach channel is measured burst by burst. A bit error probability (BEP)can be used for measuring link quality. The BEP includes MEAN_BEP andCV_BEP. The BEP is measured for all used modulation schemes. Forexample, if a system supports Gaussian minimum shift keying (GMSK),8-phase shift keying (8-PSK), 16-quadrature amplitude modulation(16-QAM), and 32-QAM, then the MEAN_BEP and CV_BEP are measured for allfour modulation schemes.

In a step 250, the MS reports to the network the link quality computedfor a modulation scheme to be reported. The MS can report the linkquality through a packet associated control channel (PACCH) such as byusing an EGPRS packet downlink Ack/Nack type 2 message.

The EGPRS packet downlink Ack/Nack type 2 message indicates states ofreceived downlink radio blocks, and is used to report a downlink channelstate.

Table 7 below shows an example of an IE included in the EGPRS packetdownlink Ack/Nack type 2 message.

TABLE 7 < EGPRS Packet Downlink Ack/Nack Type 2 message content > ::= ...  { 0 | 1 < EGPRS Channel Quality Report Type 2 : < EGPRS  ChannelQuality Report Type 2 IE > >}  < EGPRS Ack/Nack Description : < EGPRSAck/Nack Description  IE >>  ...

The ‘EGPRS Ack/Nack Description’ Information Element includes an RLCparameter indicating an Ack or a Nack for a group of RLC data blocks.

An ‘EGPRS Channel Quality Report Type 2’ Information Element showsdownlink quality. An example thereof is shown in Table 8 below.

TABLE 8 < EGPRS Channel Quality Report Type 2 > ::=  < EGPRS BEP LinkQuality Measurements Type 2 : < EGPRS BEP Link Quality Measurements Type2 IE>>  < C_VALUE : bit (6) >  < EGPRS Timeslot Link QualityMeasurements Type 2 : <EGPRS Timeslot Link Quality Measurements Type 2IE >> ;

The ‘C_VALUE’ field is a normalized Rx signal level in the MS. Theactual value of the ‘C_VALUE’ field can be calculated as disclosed inclause 10.2.3.1 of the 3GPP TS 45.008 V7.6.0 (2006-11) “Radio AccessNetwork; Radio subsystem link control (Release 7)”.

The ‘EGPRS BEP Link Quality Measurements Type 2’ Information Element isused to report an average link quality (i.e., MEAN_BEP and/or CV_BEP)throughout all assigned timeslots. That is, the ‘EGPRS BEP Link QualityMeasurements Type 2’ Information Element includes the MEAN_BEP andCV_BEP averaged throughout all timeslots in the EGPRS2. Table 9 belowshows an example of the ‘EGPRS BEP Link Quality Measurements Type 2’Information Element.

TABLE 9 <EGPRS BEP Link Quality Measurements Type 2 IE> ::=   { 0 | 1 <GMSK_MEAN_BEP : bit (5) > < GMSK_CV_BEP : bit (3) >}   { 0 | 1 <8PSK_MEAN_BEP : bit (5) > < 8PSK_CV_BEP : bit (3) > }   { 0 | 1 <QPSK_MEAN_BEP : bit (5) > < QPSK_CV_BEP : bit (3) > }   { 0 | 1 <16QAM_MEAN_BEP : bit (5) > < 16QAM_CV_BEP : bit (3) > }   { 0 | 1 <32QAM_MEAN_BEP : bit (5) > < 32QAM_CV_BEP : bit (3) > };

As indicated above, the EGPRS2 uses five modulation schemes, that is,GMSK, 8-PSK, QPSK, 16-QAM, and 32-QAM. The ‘EGPRS BEP Link QualityMeasurements Type 2’ Information Element includes MEAN_BEP and CV_BEPfor each modulation scheme.

The ‘EGPRS Timeslot Link Quality Measurements Type 2’ InformationElement is configured using a ‘EGPRS2 LINK QUALITY MEASUREMENT MODE’field, and is used to report link quality for each assigned timeslot.Table 10 below shows an example of the ‘EGPRS Timeslot Link QualityMeasurements Type 2’ Information Element.

TABLE 10 <EGPRS Timeslot Link Quality Measurements Type 2 IE> ::= { 0 |1 < BEP_MEASUREMENTS : BEP Measurement Report Struct >} { 0 | 1 <INTERFERENCE_MEASUREMENTS : Interference Measurement Report Struct >}; <BEP Measurement Report Struct > ::=  { 0 | 1 <REPORTED_MODULATION : bit(2) >  <MEAN_BEP_TN0 : bit (4) > }  { 0 | 1 < REPORTED_MODULATION : bit(2) >  <MEAN_BEP_TN1 : bit (4) > }  { 0 | 1 < REPORTED_MODULATION : bit(2) >  <MEAN_BEP_TN2 : bit (4) > }  { 0 | 1 < REPORTED_MODULATION : bit(2) >  <MEAN_BEP_TN3 : bit (4) > }  { 0 | 1 < REPORTED_MODULATION : bit(2) >  <MEAN_BEP_TN4 : bit (4) > }  { 0 | 1 < REPORTED_MODULATION : bit(2) >  <MEAN_BEP_TN5 : bit (4) > }  { 0 | 1 < REPORTED_MODULATION : bit(2) >  <MEAN_BEP_TN6 : bit (4) > }  { 0 | 1 < REPORTED_MODULATION : bit(2) >  <MEAN_BEP_TN7 : bit (4) > }; < Interference Measurement ReportStruct > ::=  { 0 | 1 < I_LEVEL_TN0 : bit (4) > }  { 0 | 1 < I_LEVEL_TN1: bit (4) > }  { 0 | 1 < I_LEVEL_TN2 : bit (4) > }  { 0 | 1 <I_LEVEL_TN3 : bit (4) > }  { 0 | 1 < I_LEVEL_TN4 : bit (4) > }  { 0 | 1< I_LEVEL_TN5 : bit (4) > }  { 0 | 1 < I_LEVEL_TN6 : bit (4) > }  { 0 |1 < I_LEVEL_TN7 : bit (4) > };

The ‘INTERFERENCE_MEASUREMENTS’ field includes a value y which iscalculated from timeslots 0 to 7. This value can be calculated asdisclosed in clause 10.2.3.1 of 3GPP TS 45.008 V7.6.0 (2006-11).

The ‘BEP_MEASUREMENTS’ struct includes both a modulation scheme and alink quality which are reported for each assigned timeslot. A‘REPORTED_MODULATION’ field indicates the reported modulation scheme. A‘MEAN_BEP_TNn’ field indicates MEAN_BEP for an n^(th) timeslot withrespect to the modulation scheme indicated using the ‘REPORTEDMODULATION’ field. Table 11 shows an example of the ‘REPORTEDMODULATION’ field for EGPRS2-A and EGPRS2-B.

TABLE 11 REPORTED_MODULATION (2 bit field) The mobile station shall, foreach of its currently assigned timeslots, report the modulation scheme(indicated using the REPORTED_MODULATION field) with which it hasreceived the largest number of blocks since the last report and shallreport the MEAN_BEP_TNx of that modulation scheme. The mapping of themodulation scheme is as follows. bit 2 1 For EGPRS2-A: 0 0 GMSK 0 1 8PSK1 0 16QAM 1 1 32QAM For EGPRS2-B: 0 0 GMSK 0 1 QPSK 1 0 16QAM 1 1 32QAM

According to the proposed method of reporting link quality, the MSselects a modulation scheme which is the most used in a specifictimeslot within all assigned timeslots since the last report, andreports the selected modulation scheme and link quality for the selectedmodulation scheme. This means that, for each assigned timeslot, the MSreports a modulation scheme, which is the most used among the receivedradio blocks, and link quality of that modulation scheme. The most usedmodulation scheme is specified for each timeslot, and the MS reports thespecified modulation scheme to the network. Therefore, link qualityreporting can be flexibly supported even if a modulation scheme is addedor modified in the EGPRS2 or an evolved system of the EGPRS2. Thenetwork can perform a link adaptation process by determining amodulation and coding scheme according to the reported link quality.

The MS can report an accurate link quality for each assigned-timeslot byreporting a link quality for the modulation scheme with which thelargest number of radio blocks is received on each of assignedtimeslots. To avoid reporting duplicated information, the MS reports alink quality for a modulation scheme in which an averaging operation isperformed throughout all assigned timeslots by using the ‘EGPRS BEP LinkQuality Measurements Type 2’ IE, and reports a link quality of the mostused modulation scheme for each assigned timeslot by using the ‘EGPRSTimeslot Link Quality Measurements Type 2’ IE.

If the network can know the link quality in the uplink radio resourcerequest operation, radio resources can be effectively assigned also inthe EGPRS2 system. Therefore, performance of the EGPRS2 system can beimproved by allowing the MS to transmit to the network the link qualityfor various modulation schemes additionally supported in the EGPRS2 byusing the packet resource request message.

The MS reports the link quality of the modulation scheme with which alargest number of radio blocks are received on each of currentlyassigned timeslots, and does not consider the use of a timeslot which isno longer used. By reporting the link quality of the modulation schemefor the largest number of radio blocks, a smallest number of radioblocks can be further surely guaranteed so that the statistical analysisis useful.

The MS reports not only the link quality but also the modulation schemewith which the largest number of radio blocks is received on each ofassigned timeslots. Accordingly, radio resources can be effectivelyused, and an overall throughput can be improved.

Meanwhile, according to GP-080266 introduced by Nokia in February of2008, a technique for multiplexing the EGPRS, EGPRS2-A and the EGPRS2-Bhas been proposed. In this technique, three modulation schemes are addedto the EGPRS2-B. That is, the 8-PSK, 16-QAM with normal symbol rate(NSR), and 32-QAM with NSR which are supported by the EGPRS2-A are addedto the GMSK, QPSK, 16-QAM with higher symbol rate (HSR), and 32-QAM withHSR which are supported by the conventional EGPRS2-B, so that theEGPRS2-B can support the GMSK, QPSK, 8-PSK, 16-QAM with NSR, 16-QAM withHSR, 32-QAM with NSR, and 32-QAM with NSR. The NSR and the HSR use thesame modulation scheme. However, a complex-valued symbol (also referredto as a modulation symbol) of a modulation scheme with the HSR has afrequency bandwidth about 1.2 times larger than a complex-valued symbolof a modulation scheme with the NSR. Since one modulation schemesupports a higher symbol rate than the other modulation scheme, the twomodulation schemes can be distinguished. For example, 16-QAM used in theconventional EGPRS2-B has a higher symbol rate than 16-QAM used in theconventional EGPRS2-A. The former is referred to as 16-QAM HSR, and thelatter is referred to as 16-QAM NSR.

When the EGPRS2-A is multiplexed to the EGPRS2-B, the ‘EGPRS BEP LinkQuality Measurements Type 2’ IE described in Table 9 above can bemodified as shown in Table 12 below.

TABLE 12 <EGPRS BEP Link Quality Measurements Type 2 IE> ::=   { 0 | 1 <GMSK_MEAN_BEP : bit (5) > < GMSK_CV_BEP : bit (3) >}   { 0 | 1 <8PSK_MEAN_BEP : bit (5) > < 8PSK_CV_BEP : bit (3) > }   { 0 | 1 <QPSK_MEAN_BEP : bit (5) > < QPSK_CV_BEP : bit (3) > }   { 0 | 1 <16QAM_HSR_MEAN_BEP : bit (5) > < 16QAM_HSR_CV_BEP : bit (3) > }   { 0 |1 < 32QAM_HSR_MEAN_BEP : bit (5) > < 32QAM_HSR_CV_BEP : bit (3) > }   {0 | 1 < 16QAM_NSR_MEAN_BEP : bit (5) > < 16QAM_NSR_CV_BEP : bit (3) > }  { 0 | 1 < 32QAM_NSR_MEAN_BEP : bit (5) > < 32QAM_NSR_CV_BEP : bit(3) > };

In a ‘BEP_MEASUREMENTS’ struct, to support additional modulationschemes, a ‘REPORTED_MODULATION’ field indicating a modulation schemereported for each timeslot may be a 3-bit field as shown in Table 13below.

TABLE 13 REPORTED_MODULATION (3 bit field) bit 3 2 1 For EGPRS2-A: 0 0 0GMSK 0 0 1 8PSK 0 1 0 16QAM NSR 0 1 1 32QAM NSR For EGPRS2-B: 0 0 0 GMSK0 0 1 QPSK 0 1 0 16QAM HSR 0 1 1 16QAM NSR 1 0 0 32QAM HSR 1 0 1 32QAMNSR

A problem occurs when the number of bits of the ‘REPORTED_MODULATION’field is increased to 3 bits only for the EGPRS2-B. The problem is thata total size of the ‘BEP_MEASUREMENTS’ struct increases. In addition, inmost cases, the possibility of concurrently using seven modulationschemes during one reporting period is low. Therefore, the number ofbits of the ‘REPORTED_MODULATION’ field may be set to two bits.

In a method to be described below, the ‘REPORTED_MODULATION’ field isset to two bits and is configured by selecting four modulation schemesfrom seven modulation schemes used in the EGPRS2-B. Modulation schemesselected for configuring the ‘REPORTED_MODULATION’ field are referred toas candidate modulation schemes. The MS selects the most used modulationscheme from the candidate modulation schemes, and reports link qualityfor the selected modulation scheme. Regarding modulation schemes whichwere not selected to configure the ‘REPORTED_MODULATION’ field, linkquality is not reported.

Table 14 below shows an example of selecting four modulation schemesother than modulation schemes of the EGPRS2-A to be multiplexed. This isa case where modulation schemes added for multiplexing are notfrequently used in the EGPRS2-B.

TABLE 14 REPORTED_MODULATION (2 bit field) bit 2 1 For EGPRS2-A: 0 0GMSK 0 1 8PSK 1 0 16QAM NSR 1 1 32QAM NSR For EGPRS2-B: 0 0 GMSK 0 1QPSK 1 0 16QAM HSR 1 1 32QAM HSR

Table 15 below shows another example of selecting four modulationschemes. This is to enable the network to consider a link qualitydifference between the HSR and the NSR.

TABLE 15 REPORTED_MODULATION (2 bit field) bit 2 1 For EGPRS2-A: 0 0GMSK 0 1 8PSK 1 0 16QAM NSR 1 1 32QAM NSR For EGPRS2-B: 0 0 16QAM NSR 01 16QAM HSR 1 0 32QAM NSR 1 1 32QAM HSR

Table 16 below shows another example of selecting four modulationschemes. Herein, the GMSK is replaced with the 8-PSK. Since the EGPRS2-Bcan be used to obtain a higher data rata than the EGPRS2-A, the GMSK isreplaced with the 8-PSK by considering a possibility of reporting the8-PSK instead of the GMSK for the further effective use of resources.

TABLE 16 REPORTED_MODULATION (2 bit field) bit 2 1 For EGPRS2-A: 0 0GMSK 0 1 8PSK 1 0 16QAM NSR 1 1 32QAM NSR For EGPRS2-B: 0 0 QPSK 0 18PSK 1 0 16QAM HSR 1 1 32QAM HSR

With respect to the selected four modulation schemes, the MS reports,for each assigned timeslots, link quality for the modulation scheme mostused among received radio blocks. The MS does not report link qualityfor any modulation scheme other than the four selected modulationschemes.

The above examples are for exemplary purposes only, and thus the fourmodulation schemes can be selected from the seven modulation schemessupporting the EGPRS2-B in various combinations. In addition, theconfiguration of the ‘REPORTED_MODULATION’ field may vary from one MS toanother or from one time to another.

Generally speaking, the above examples relates to determining a subsetof modulation schemes among a set of available modulation schemes andapplying the criterion for selecting a modulation scheme to the solemodulation schemes of the subset. Depending on the embodiment, the setand the subset can be formed of any number of modulations schemes. Inother words, the MS does not seem to need to take into account all of 7modulation schemes for EGPRS2 channel quality reporting during thereporting period.

When the link quality reporting is instructed through the packetdownlink message, the MS can report link quality only for the most usedmodulation scheme since the last report. If link quality is to bereported for two modulation schemes, the MS reports link quality of thetwo modulation schemes starting from the most used modulation scheme. Iflink quality is to be reported for three modulation schemes, the MSreports link quality of the three modulation schemes starting from themost used modulation scheme. That is, link quality is reported not forall modulation schemes but for some selected modulation schemes, andthus an overhead resulted from link quality reporting can be avoided.

A problem occurs when a plurality of different modulation schemes havethe same number of transmitted radio blocks. That is, the problem is asto with which condition the MS has to report channel quality if linkquality is to be reported for two modulation schemes and three or moremodulation scheme (e.g., GMSK, 16-QAM, and 32-QAM) have the same numberof received radio blocks.

In such a situation when there is a plurality of different modulationschemes with the same number of received radio blocks, a modulationscheme for reporting link quality can be selected in various manners.The selection of the modulation scheme may be predetermined in the MS ormay be reported by the network to the MS.

According to an embodiment, link quality is reported for two high-ordermodulation schemes. For example, if the GMSK, 16-QAM, and 32-QAM aredifferent modulation schemes with the same number of most received radioblocks received by the MS, the MS reports link quality for the 16-QAMand 32-QAM which are higher order modulation schemes than the GMSK. Inother words, for EGPRS2 channel quality reporting per timeslot, if thereare more than one modulation scheme having the same number and thelargest number of blocks on a currently assigned timeslot, the MS shallreport the MEAN_BEP_TNx for the highest order modulation scheme amongthose modulation schemes on that timeslot.

According to another embodiment, link quality is reported for twolow-order modulation schemes. For example, if the GMSK, 16-QAM, and32-QAM are different modulation schemes with the same number of mostreceived radio blocks received by the MS, the MS reports link qualityfor the GMSK and 16-QAM.

According to another embodiment, link quality is reported for themodulation schemes with the lower MEAN_BEP. For example, if the GMSK,16-QAM, and 32-QAM are different modulation schemes with the number ofsame most received radio blocks received by the MS where GMSK_MEAN_BEPis 0.001, 16QAM_MEAN_BEP is 0.003, 32QAM_MEAN_BEP is 0.005, and thenlink quality is reported for the GMSK and 16-QAM.

According to another embodiment, link quality is reported for amodulation scheme with a higher MEAN_BEP. For example, if the GMSK,16-QAM, and 32-QAM are different modulation schemes with the same numberof most received radio blocks received by the MS where GMSK_MEAN_BEP is0.001, 16QAM_MEAN_BEP is 0.003, 32QAM_MEAN_BEP is 0.005, and then linkquality is reported for the 16-QAM and 32-QAM.

Depending on the embodiment, the MS may report the link quality (i.e.,MEAN_BEP_TN and CV_BEP_TN) using a timeslot unit, that is to say pertimeslot or may report the average link quality (i.e., MEAN_BEP andCV_BEP) for a plurality of timeslots, that is to say throughout allassigned timeslots. The network can perform a link adaptation process bydetermining a modulation and coding scheme according to the reportedlink quality.

According to a method of the present invention, link quality is reportednot for all but for some modulation schemes. Therefore, a signallingoverhead is reduced, and performance deterioration is minimized in alink adaptation process. In addition, even in a case where there is aplurality of different modulation schemes with the same number ofreceived radio blocks, an overall system performance can be increased bydefining a modulation scheme whose link quality is to be reported.

FIG. 5 is a flow diagram illustrating a method of reporting link qualityaccording to another embodiment of the present invention.

Referring to FIG. 5, in a step S310, a BS transmits a control message toan MS. The control message includes a specific signalling‘SWITCHING_MODULATION’ field for switching a configuration of a‘REPORTED_MODULATION’ field. For example, when a packet downlinkassignment message is used as the control message, the message can beconfigured as shown in Table 17 below.

TABLE 17 < Packet Downlink Assignment message content > ::=  ...   { 0 |1 < EGPRS Window Size : < EGPRS Window Size IE >>     <LINK_QUALITY_MEASUREMENT_MODE : bit (2) >     < SWITCHING_MODULATION :bit(1) >     < EGPRS2_LINK_QUALITY_MEASUREMENT_MODE :     bit (1) >    { 0 | 1 < BEP_PERIOD2 : bit(4) > } }  ...

As shown in Table 18 below, the ‘SWITCHING_MODULATION’ field may beincluded as a part of the ‘BEP_MEASUREMENTS’ struct of the ‘EGPRSTimeslot Link Quality Measurements Type 2’ IE.

TABLE 18 <EGPRS Timeslot Link Quality Measurements Type 2 IE> ::= { 0 |1 < BEP_MEASUREMENTS : BEP Measurement Report Struct >} { 0 | 1 <INTERFERENCE_MEASUREMENTS : Interference Measurement Report Struct >}; <BEP Measurement Report Struct > ::=   < SWITCHING_MODULATION : bit(1) > { 0 | 1 <REPORTED_MODULATION : bit (2) >   <MEAN_BEP_TN0 : bit (4) > } { 0 | 1 < REPORTED_MODULATION : bit (2) >  <MEAN_BEP_TN1 : bit (4) > } { 0 | 1 < REPORTED_MODULATION : bit (2) >  <MEAN_BEP_TN2 : bit (4) > } { 0 | 1 < REPORTED_MODULATION : bit (2) >  <MEAN_BEP_TN3 : bit (4) > } { 0 | 1 < REPORTED_MODULATION : bit (2) >  <MEAN_BEP_TN4 : bit (4) > } { 0 | 1 < REPORTED_MODULATION : bit (2) >  <MEAN_BEP_TN5 : bit (4) > } { 0 | 1 < REPORTED_MODULATION : bit (2) >  <MEAN_BEP_TN6 : bit (4) > } { 0 | 1 < REPORTED_MODULATION : bit (2) >  <MEAN_BEP_TN7 : bit (4) > };< Interference Measurement Report Struct > ::=  { 0 | 1 < I_LEVEL_TN0 :bit (4) > }  { 0 | 1 < I_LEVEL_TN1 : bit (4) > }  { 0 | 1 < I_LEVEL_TN2: bit (4) > }  { 0 | 1 < I_LEVEL_TN3 : bit (4) > }  { 0 | 1 <I_LEVEL_TN4 : bit (4) > }  { 0 | 1 < I_LEVEL_TN5 : bit (4) > }  { 0 | 1< I_LEVEL_TN6 : bit (4) > }  { 0 | 1 < I_LEVEL_TN7 : bit (4) > };

According to the value of the ‘SWITCHING_MODULATION’ field, theconfiguration of the ‘REPORTED_MODULATION’ field can be switched. Forexample, when the ‘SWITCHING_MODULATION’ field consists of one bit, ifthe value of this field is ‘0’, the ‘REPORTED_MODULATION’ field of Table14 can be used, and if the value of this field is ‘1’, the‘REPORTED_MODULATION’ field of Table 15 can be used. Alternatively, whenthe ‘SWITCHING_MODULATION’ consists of two bits, if the value of thefield is ‘00’, the ‘REPORTED_MODULATION’ field of Table 14 can be used,if the value of the field is ‘01’, the ‘REPORTED_MODULATION’ field ofTable 15 can be used, and if the value of the field is ‘10’, the‘REPORTED_MODULATION’ field of Table 16 can be used.

In a step S320, by using the ‘REPORTED_MODULATION’ indicated using the‘SWITCHING_MODULATION’ field, the MS selects a modulation scheme whichis the most used in a specific timeslot included in all assignedtimeslots by radio blocks received since the last report, and reportsthe selected modulation scheme and link quality for the selectedmodulation scheme.

Now, a method of assigning radio resources for an uplink packettransmission in an EGPRS/EGPRS2 system will be described.

In order to establish an uplink TBF, an MS transmits to a network apacket channel request message through a packet random access channel(PRACH) or a random access channel (RACH). There are two types (i.e.,one-phase access and two-phase access) of operations in uplink TBFestablishment.

The one-phase access is supported only when a radio link control (RLC)mode is an acknowledge mode. Since a multi-slot class is alsotransmitted when the uplink TBF is requested by the MS, uplink TBFassignment can be achieved without any additional message between the MSand a network. This means that a multi-slot assignment is possiblestarting from an initial stage according to the configuration of the MSbecause the network knows the multi-slot class of the MS which hasrequested the uplink TBF. However, a contention may occur in some cases.When a plurality of MSs transmits (EGPRS/EGPRS2) packet channel requestmessages through the same PRACH or RACH, even if TBFs are not assignedto the MSs, the MSs may perform uplink transmission by considering thatthe TBFs are assigned, which results in the contention. To resolve thecontention, the MS transmits a temporary logical link identifier (TLLI)by appending it to a subsequent RLC data block through the PDTCH. TheTLLI is an MS identifier. If a packet uplink acknowledgment(ACK)/negative-acknowledgement (NACK) message received from the networkincludes the same TLLI, the MS determines that the resolution of thecontention is completed. Thus, in the subsequent PDTCH, data istransmitted without appending the TLLI. If the received TLLI isdifferent from the TLLI transmitted by the MS, the resolution of thecontention is determined as a failure, and thus a TBF release operationis performed.

FIG. 6 is a flow diagram showing a method of requesting uplink radioresources according to an embodiment of the present invention.

Referring to FIG. 6, in a step S410, an MS transmits an (EGPRS/EGPRS2)packet channel request message to a network through a PRACH or a RACH inorder to establish an uplink TBF. The (EGPRS/EGPRS2) packet channelrequest message includes an access type indicating either one-phaseaccess or two-phase access and a parameter required to specify radioresources. The packet channel request message is transmitted through thePRACH or the RACH using an access burst. This may be found in clause11.2.5 of 3GPP TS 44.060 V7.8.0 (2007-03) “Technical Specification GroupGSM/EDGE Radio Access Network; General Packet Radio Service (GPRS);Mobile Station (MS)-Base Station System (BSS) interface; Radio LinkControl/Medium Access Control (RLC/MAC) protocol (Release 7)”. The EGPRSpacket channel request message may be found in clause 11.2.5a of 3GPP TS44.060 V7.8.0 (2007-03).

In a step S420, if the (EGPRS/EGPRS2) packet channel request messageindicates a two-phase access request, the network transmits a packetuplink assignment message on a packet common control channel (PCCCH) inorder to assign a single radio block on an uplink PDCH. If the packetchannel request message indicates the two-phase access, the network canassign multi-blocks on the uplink PDCH.

In a step S430, upon receiving the packet uplink assignment message, theMS transmits a packet resource request message in a radio block assignedusing the packet uplink assignment message. The packet resource requestmessage is a message transmitted on a packet associated control channel(PACCH) in order to request a change of the assigned uplink radioresource. The packet resource request message includes an EGPRS2 linkquality and a channel request description for uplink radio resourceassignment. That is, a link quality for modulation schemes additionallysupported in the EGPRS2 is included in the packet resource requestmessage. Content of the packet resource request message will bedescribed below.

When the packet resource request message is transmitted, the MS starts aresource request timer. The resource request timer is for evaluating asuccess or failure of a packet access procedure. The resource requesttimer operates for each TBF. Conditions of starting, stopping, andaction at expiry of the resource request timer is shown in Table 19below.

TABLE 19 Resource Request Timer started At sending the PACKET RESOURCEREQUEST message. A separate instance of the resource request timer isstarted for each TBF for which resources were requested. stopped Onreceipt of a PACKET UPLINK ASSIGNMENT, MULTIPLE TBF UPLINK ASSIGNMENT,PACKET TIMESLOT RECONFIGURE or a MULTIPLE TBF TIMESLOT RECONFIGUREmessage that assigns resources to an uplink TBF. On receipt of a PACKETACCESS REJECT message that rejects one or more uplink TBFs. action atexpiry Reinitiate the packet access procedure or retransmit the PACKETRESOURCE REQUEST message.

In a step S440, as indicated in the dotted line in FIG. 6, if the MSdesires to transmit additional information regarding radio accesscapability, the MS can transmit an additional MS radio access capabilitymessage together with an indication of an ‘ADDITIONAL MS RAC INFORMATIONAVAILABLE’ field included in the packet resource request message.

In a step S450, in response to the packet resource request message, thenetwork transmits the packet uplink assignment message and thus reportsthe assigned radio resources to the MS. The network transmits the packetuplink assignment message including a TLLI of the MS on the PACCH byusing the access capability of the MS. The MS determines a success orfailure of a contention resolution by evaluating the TLLI included inthe packet uplink assignment message.

Alternatively, instead of transmitting the packet uplink assignmentmessage, if the packet access of the MS is rejected, the network maytransmit a packet access reject message. Upon receiving the packetaccess reject message, the MS stops the resource request timer andreports a packet access failure to an upper layer.

Now, a packet resource request message including information regardingthe EGPRS2 link quality will be described. Link quality for modulationschemes additionally supported in EGPRS2 is transmitted using the packetresource request message.

Table 20 below shows an example of an information element (IE) includedin the packet resource request message for the report of the EGPRS2 linkquality.

TABLE 20 < Packet Resource Request message content > ::=  { 0 | 1 <ACCESS_TYPE : bit (2) > }  {0 < Global TFI : < Global TFI IE > >   | 1 <TLLI/ G-RNTI : < TLLI/ G-RNTI IE > > }   < Channel Request Description :< Channel Request   Description IE > >   < ADDITIONAL MS RAC INFORMATIONAVAILABLE : bit (1) >  ...  {0 | 1 < EGPRS BEP Link Quality MeasurementsType 2 : < EGPRS BEP Link Quality Measurements Type 2 IE>>}  {0 | 1 <EGPRS Timeslot Link Quality Measurements Type 2 : <EGPRS Timeslot LinkQuality Measurements Type 2 IE >>}  ...

The ‘ACCESS_TYPE’ field includes a reason of access request. Forexample, this field may specify a one or a two-phase access request, apage response, a cell update, and a mobility management procedure.

The ‘Global TFI’ field includes a TFI for the uplink TBF of the MS. Atemporary logical link identity (TLLI) is in association with a GPRSsubscriber, and is defined in 3GPP TS 23.003. A G-RNTI is defined in3GPP TS 44.160.

The ‘Channel Request Description’ IE describes information necessary torequest uplink radio resources. This IE includes information regarding aradio priority of the requested TBF, an RLC mode of the requested TBF,an amount of an RLC data block to be transmitted by the MS, etc.

The ‘ADDITIONAL MS RAC INFORMATION AVAILABLE’ field indicates whether totransmit additional information regarding radio access capability of theMS.

FIG. 7 is a flow diagram showing a method of requesting uplink radioresources according to another embodiment of the present invention.

This embodiment differs from the embodiment described with reference toFIG. 6 in that it is initiated by the network directly.

Referring to FIG. 7, in a step S510, a network transmits a packet uplinkassignment message to an MS on a PCCCH in order to instruct transmissionof a packet resource request message.

In a step S520, upon receiving the packet uplink assignment message, theMS transmits the packet resource request message in a radio blockassigned using the packet uplink assignment message on a PACCH. Thepacket resource request message includes an EGPRS2 link quality and achannel request description for uplink radio resource assignment.Additional details have been described previously with reference to stepS430.

When the packet resource request message is transmitted, the MS starts aresource request timer.

The method then comprises a step S530 performed in a manner similar withstep S440.

The method further comprises a step S540 performed in a manner similarwith step S450.

In other words, when a mobile station requests EGPRS2 resources byPACKET RESOURCE REQUEST message, the information on the link qualitymeasurements is sent if the related IEs are available and if those IEswould not cause the message to expand beyond one RLC/MAC control block.

The IEs and tables described above are for exemplary purposes only, andthus names of fields included in each IE, the number of bits of eachfield, and arrangement of the fields can be modified.

According to the present invention, a mobile station can report linkquality for modulation and coding schemes additionally provided in anenhanced general packet radio service phase 2 (EGPRS2) system.Therefore, the performance of a link adaptation process can be improved.

Furthermore, link quality is reported not for all but for somemodulation schemes. Therefore, a signalling overhead is reduced, andperformance deterioration is minimized in a link adaptation process. Inaddition, even in a case where there is a plurality of differentmodulation schemes with the same number of received radio blocks, anoverall system performance can be increased by defining a modulationscheme whose link quality is to be reported.

Mobile stations can also transmit to a network a link quality formodulation schemes additionally supported in an enhanced general packetradio service phase 2 (EGPRS2) system, so that the network caneffectively assign the uplink radio resources to each mobile station.Therefore, performance of uplink transmission can be improved.

The present invention can be implemented with hardware, software, orcombination thereof. Regarding hardware implementation, the presentinvention can be implemented with one of an application specificintegrated circuit (ASIC), a digital signal processor (DSP), aprogrammable logic device (PLD), a field programmable gate array (FPGA),a processor, a controller, a microprocessor, other electronic units, andcombination thereof, which are designed to perform the aforementionedfunctions. Regarding software implementation, the present invention canbe implemented with a module for performing the aforementionedfunctions. Software is storable in a memory unit and executed by aprocessor. Various means widely known to those skilled in the art can beused as the memory unit or the processor.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those skilled in the art that various changes in form and details maybe made therein without departing from the spirit and scope of theinvention as defined by the appended claims. The exemplary embodimentsshould be considered in descriptive sense only and not for purposes oflimitation. Therefore, the scope of the invention is defined not by thedetailed description of the invention but by the appended claims, andall differences within the scope will be construed as being included inthe present invention.

1. A method of reporting link quality for radio blocks using a pluralityof modulation schemes, the method comprising, performed in a mobileterminal: determining a link quality parameter for each modulationscheme and each timeslot assigned to the mobile terminal; determiningthe number of times each modulation scheme is used in the assignedtimeslots over a reporting period; selecting at least one modulationscheme; and reporting to a network the selected modulation scheme andcorresponding link quality information, wherein, selecting comprises:determining a subset of modulation schemes among a set of availablemodulation schemes; and selecting modulation schemes among the solemodulation schemes of said subset.
 2. The method of claim 1, wherein theset of available modulation schemes comprises seven modulations schemesand the subset comprises four modulation schemes.
 3. The method of claim1, wherein the plurality of available modulation schemes comprise GMSK,QPSK, 8-PSK, 16-QAM normal symbol rate (NSR), 16-QAM higher symbol rate(HSR), 32-QAM NSR, and 32-QAM HSR.
 4. The method of claim 1, whereinselecting a modulation scheme comprises selecting the modulation schemewhich is the most used in one timeslot and among the modulation schemesof the subset.
 5. The method of claim 1, wherein said link qualityinformation comprises the link quality parameter for each selectedmodulation scheme for each timeslot.
 6. The method of claim 1, whereinsaid link quality information comprises an averaged value of the linkquality parameters of each selected modulation scheme over severalassigned timeslots.
 7. The method of claim 1, wherein determining thelink quality parameter comprises: measuring a bit error probability(BEP) per burst; averaging the measured BEP per radio block; andcomputing the link quality parameter based on the measured and averagedBEP per modulation scheme and per time slot.
 8. A mobile terminalcomprising a radio frequency (RF) unit adapted to receive radio blocksusing a plurality of modulation schemes and a processor coupled with theRF unit and adapted for: determining a link quality parameter for eachmodulation scheme and each timeslot assigned to the mobile terminal;determining the number of times each modulation scheme is used in theassigned timeslots over a reporting period; selecting at least onemodulation scheme; and reporting to a network the selected modulationscheme and corresponding link quality information, wherein, selectingcomprises: determining a subset of modulation schemes among a set ofavailable modulation schemes; and selecting modulation schemes among thesole modulation schemes of said subset.
 9. The terminal of claim 8,wherein the set of available modulation schemes comprises sevenmodulations schemes and the subset comprises four modulation schemes.10. The terminal of claim 8, wherein the plurality of availablemodulation schemes comprise GMSK, QPSK, 8-PSK, 16-QAM normal symbol rate(NSR), 16-QAM higher symbol rate (HSR), 32-QAM NSR, and 32-QAM HSR. 11.The terminal of claim 8, wherein the processor is adapted for selectingthe modulation scheme which is the most used in one timeslot and amongthe modulation schemes of the subset.
 12. The terminal of claim 8,wherein said link quality information comprises the link qualityparameter for each selected modulation scheme for each timeslot.
 13. Theterminal of claim 8, wherein said link quality information comprises anaveraged value of the link quality parameters of each selectedmodulation scheme over several assigned timeslots.
 14. The terminal ofclaim 8, wherein the processor is adapted for determining the linkquality parameter by: measuring a bit error probability (BEP) per burst;averaging the measured BEP per radio block; and computing the linkquality parameter based on the measured and averaged BEP per modulationscheme and per time slot.